Oxidation of Organosolv Lignin in a Novel Surfactant-free Microemulsion Reactor
Juanhua Kong, Lixia Li, Xin Luo, Qiang Zeng, Xiumin Chen, Zhenping Cai, Jinxing Long, Sijie Liu* and Xuehui Li*
School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, China.
Hongyan He
Beijing Key Laboratory of Ionic Liquids Clean Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
Yingying Wang
South China Advanced Institute for Soft Matter Science and Technology, South China University of Technology, Guangzhou, 510640, China.
Lignin is considered as a promising substitute for fossil resources, but the efficient conversion of the lignin remains a huge challenge due to its structural complexity and immiscibility with typical solvents. Herein, a series of surfactant-free microemulsion reactors comprised of octane, water and n-propanol were designed and their corresponding phase behaviors alongside their ability to intensify oxidative depolymerization of lignin was explored. Experimental results show that the phenolic monomer yield improves substantially (40-500 wt.%) when the novel microemulsion systems are employed by comparison with processes performed in a single solvent. Detailed characterizations also suggest that the above intensification is rationalized by the solubilization effect of the microemulsion system, which arise as a consequence of directional aggregation of lignin at the microemulsion interface.